/*
public class ListNode {
    int val;
    ListNode next = null;

    ListNode(int val) {
        this.val = val;
    }
}*/
public class Solution {
    public ListNode FindKthToTail(ListNode head,int k) {
        if(head==null||k==0){
            return null;
        }
        ListNode fast;
        ListNode slow;
        fast=head;
        slow=head;
        for(int i=0;i<k;i++){
            if(fast==null){
                return null;
            }
            fast=fast.next;
        }
        while(fast!=null){
            fast=fast.next;
            slow=slow.next;
        }
        return slow;

    }
}